#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include "threadpool.h"           //总共有三类线程，主线程负责分配任务，子线程负责取走任务，管理线程负责控制子线程数量

#define DEFAULT_TIME 10                 /*10s检测一次*/
#define MIN_WAIT_TASK_NUM 10            /*如果queue_size > MIN_WAIT_TASK_NUM 添加新的线程到线程池*/ 
#define DEFAULT_THREAD_VARY 10          /*每次创建和销毁线程的个数*/
#define true 1
#define false 0

typedef struct 
{
    void *(*function)(void *);          /* 函数指针，回调函数 */
    void *arg;                          /* 上面函数的参数 */
} threadpool_task_t;                    /* 各子线程任务结构体 */

/* 描述线程池相关信息 */     
struct threadpool_t 
{
    pthread_mutex_t lock;               /* 用于锁住本结构体 */    
    pthread_mutex_t thread_counter;     /* 记录忙状态线程个数de琐 -- busy_thr_num */

    pthread_cond_t queue_not_full;      /* 当任务队列满时，添加任务的线程阻塞，等待此条件变量 */
    pthread_cond_t queue_not_empty;     /* 任务队列里不为空时，通知等待任务的线程 */

    pthread_t *threads;                 /* 存放线程池中每个线程的tid。数组 */
    pthread_t adjust_tid;               /* 存管理线程tid */
    threadpool_task_t *task_queue;      /* 任务队列(数组首地址) */

    int min_thr_num;                    /* 线程池最小线程数 */
    int max_thr_num;                    /* 线程池最大线程数 */
    int live_thr_num;                   /* 当前存活线程个数 */
    int busy_thr_num;                   /* 忙状态线程个数 */
    int wait_exit_thr_num;              /* 要销毁的线程个数 */

    int queue_front;                    /* task_queue队头下标 */
    int queue_rear;                     /* task_queue队尾下标 */
    int queue_size;                     /* task_queue队中实际任务数 */
    int queue_max_size;                 /* task_queue队列可容纳任务数上限 */

    int shutdown;                       /* 标志位，线程池使用状态，true或false */
};

void *threadpool_thread(void *threadpool);

void *adjust_thread(void *threadpool);

int is_thread_alive(pthread_t tid);
int threadpool_free(threadpool_t *pool);




//threadpool_create(3,100,100);  
threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size)  //子线程最小个数  最大个数，任务池中任务最大个数
{
    int i;
    threadpool_t *pool = NULL;
          do 
         {
                     if((pool = (threadpool_t *)malloc(sizeof(threadpool_t))) == NULL) 
	     {  
                            printf("malloc threadpool fail");
                              break;                                      /*跳出do while*/
                      }

        pool->min_thr_num = min_thr_num;          //一开始创建子线程的时候，创建的线程个数
        pool->max_thr_num = max_thr_num;
        pool->busy_thr_num = 0;                        //忙碌线程数
        pool->live_thr_num = min_thr_num;               /* 活着的线程数 初值=最小线程数 */
        pool->wait_exit_thr_num = 0;                  //需要退出的线程个数，任务少的时候
        pool->queue_size = 0;                           /* 有0个产品 */  //任务数
        pool->queue_max_size = queue_max_size;                          //最大任务数 
        pool->queue_front = 0;                          
        pool->queue_rear = 0;
        pool->shutdown = false;                         /* 不关闭线程池 */

        /* 根据最大线程上限数， 给工作线程数组开辟空间, 并清零 */
        pool->threads = (pthread_t *)malloc(sizeof(pthread_t)*max_thr_num); 
                             if (pool->threads == NULL) 
		{
                                    printf("malloc threads fail");
                                    break;
                                }
        memset(pool->threads, 0, sizeof(pthread_t)*max_thr_num);

        /* 队列开辟空间 */  //为任务池开辟空间
        pool->task_queue = (threadpool_task_t *)malloc(sizeof(threadpool_task_t)*queue_max_size);
                              if (pool->task_queue == NULL) 
		{
                                    printf("malloc task_queue fail\n");
                                    break;
                                 }

        /* 初始化互斥琐、条件变量 */ //if里只要有一个失败，就都失败了
        if (pthread_mutex_init(&(pool->lock), NULL) != 0
                || pthread_mutex_init(&(pool->thread_counter), NULL) != 0
                || pthread_cond_init(&(pool->queue_not_empty), NULL) != 0
                || pthread_cond_init(&(pool->queue_not_full), NULL) != 0)
                {
            printf("init the lock or cond fail\n");
            break;
                    }

		//启动工作线程
		pthread_attr_t attr;
		pthread_attr_init(&attr);
		pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
                                 for (i = 0; i < min_thr_num; i++) 
		{
                                            pthread_create(&(pool->threads[i]), &attr, threadpool_thread, (void *)pool);/*pool指向当前线程池*/
                                            printf("start thread 0x%x...\n", (unsigned int)pool->threads[i]);
                                  }

		//创建管理者线程
        pthread_create(&(pool->adjust_tid), &attr, adjust_thread, (void *)pool);

        return pool;

    } while (0);

	/* 前面代码调用失败时,释放poll存储空间 */
    threadpool_free(pool);

    return NULL;
}










/* 向线程池中 添加一个任务 */
//threadpool_add(thp, process, (void*)&num[i]);   /* 向线程池中添加任务 process: 小写---->大写*/

int threadpool_add(threadpool_t *pool, void*(*function)(void *arg), void *arg)
{
    pthread_mutex_lock(&(pool->lock));         //共享资源枷锁

    /* ==为真，队列已经满， 调wait阻塞 */
                  while ((pool->queue_size == pool->queue_max_size) && (!pool->shutdown)) 
	{
                       pthread_cond_wait(&(pool->queue_not_full),    &(pool->lock));  //等待完成任务的子线程来通知
                 }

                if (pool->shutdown) 
	{
                       pthread_cond_broadcast(&(pool->queue_not_empty));           //通知所有的阻塞在 queue_not_empty位置的子线程解除阻塞
                       pthread_mutex_unlock(&(pool->lock));                                 //解锁
                       return 0;
                 }
 
                   /* 清空 工作线程 调用的回调函数 的参数arg */
                 if (pool->task_queue[pool->queue_rear].arg != NULL) 
	{
                         pool->task_queue[pool->queue_rear].arg = NULL;
                 }

    /*添加任务到任务队列里*/
    pool->task_queue[pool->queue_rear].function = function;            //从队尾添加 任务
    pool->task_queue[pool->queue_rear].arg = arg;
    pool->queue_rear = (pool->queue_rear + 1) % pool->queue_max_size;       /* 队尾指针移动, 模拟环形 */
    pool->queue_size++;                                        //任务数加加

    /*添加完任务后，队列不为空，唤醒线程池中 等待处理任务的线程*/
    pthread_cond_signal(&(pool->queue_not_empty));         
    pthread_mutex_unlock(&(pool->lock));

    return 0;
}








 
/* 线程池中各个工作线程 *///子线程
void *threadpool_thread(void *threadpool)
{
    threadpool_t *pool = (threadpool_t *)threadpool;   //获取全局变量
    threadpool_task_t task;

                while (true) 
	{
                         /* Lock must be taken to wait on conditional variable */
                         /*刚创建出线程，等待任务队列里有任务，否则阻塞等待任务队列里有任务后再唤醒接收任务*/
                        pthread_mutex_lock(&(pool->lock));

                                           /*queue_size == 0 说明没有任务，调 wait 阻塞在条件变量上, 若有任务，跳过该while*/
                                 while ((pool->queue_size == 0) && (!pool->shutdown)) 
		{  
                                       printf("thread 0x%x is waiting\n", (unsigned int)pthread_self());
                                       pthread_cond_wait(&(pool->queue_not_empty), &(pool->lock));//如果没有任务就阻塞到这，要么是主线程通知去任务，要么是管理线程通知要退出

                                                /*清除指定数目的空闲线程，如果要结束的线程个数大于0，结束线程*/
                                                 if (pool->wait_exit_thr_num > 0)    //管理线程设置的需要退出的线程个数 ，要是大于零就需要退出，主线程无法设置这个值所有取任务跳过此代码
			{
                                                      pool->wait_exit_thr_num--;

                                                               /*如果线程池里线程个数大于最小值时可以结束当前线程*/   //线程池里 最小维持一个最小值
                                                                if (pool->live_thr_num > pool->min_thr_num) 
				{
                                                                     printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
                                                                     pool->live_thr_num--;                                 //或者的线程--
                                                                      pthread_mutex_unlock(&(pool->lock));        //退出前 线程解锁
			                       //pthread_detach(pthread_self());
                                                                        pthread_exit(NULL);               //退出
                                                                 }
                                                 }
                                    }


                                 /*如果指定了true，要关闭线程池里的每个线程，自行退出处理---销毁线程池*/
                                  if (pool->shutdown) 
		{
                                               pthread_mutex_unlock(&(pool->lock));        //解锁
                                                 printf("thread 0x%x is exiting\n", (unsigned int)pthread_self());
                                               //pthread_detach(pthread_self());
                                             pthread_exit(NULL);     /* 线程自行结束 */
                                  }

             /*从任务队列里获取任务, 是一个出队操作*/
        task.function = pool->task_queue[pool->queue_front].function;   //从队头取任务   function是回调函数
        task.arg = pool->task_queue[pool->queue_front].arg;         //arg是回调函数的参数

        pool->queue_front = (pool->queue_front + 1) % pool->queue_max_size;       /* 出队，模拟环形队列 */
        pool->queue_size--;  //当前线程的任务数 --

        /*通知可以有新的任务添加进来*/
        pthread_cond_broadcast(&(pool->queue_not_full));  //广播通知  会唤醒主线程 添加任务

        /*任务取出后，立即将 线程池琐 释放*/
        pthread_mutex_unlock(&(pool->lock));


        /*执行任务*/ 
        printf("thread 0x%x start working\n", (unsigned int)pthread_self());
        pthread_mutex_lock(&(pool->thread_counter));                            /*忙状态线程数变量琐*/  //加小锁 可以换成大锁
        pool->busy_thr_num++;                                                   /*忙状态线程数+1*/   //锁这个   
        pthread_mutex_unlock(&(pool->thread_counter));                  //解锁

        (*(task.function))(task.arg);                                           /*执行回调函数任务*/    task.function本身是指针，加*代表函数
        //task.function(task.arg);                                              /*执行回调函数任务*/

        /*任务结束处理*/ 
        printf("thread 0x%x end working\n", (unsigned int)pthread_self());
        pthread_mutex_lock(&(pool->thread_counter));          //加小锁 
        pool->busy_thr_num--;                                       /*处理掉一个任务，忙状态数线程数-1*/
        pthread_mutex_unlock(&(pool->thread_counter));        //解锁
    }

    pthread_exit(NULL);
}












/* 管理线程 */
void *adjust_thread(void *threadpool)
{
    int i;
    threadpool_t *pool = (threadpool_t *)threadpool;  //获取全局结构体的指针
                 while (!pool->shutdown)         //主线程控制的 是否退出。
	{

                          sleep(DEFAULT_TIME);                                    /*定时 对线程池管理*/    //一开始 ，还不需要管理

                          pthread_mutex_lock(&(pool->lock));              //枷锁
                          int queue_size = pool->queue_size;                      /* 关注 任务数 */     //获取队列中任务数的多少
                          int live_thr_num = pool->live_thr_num;                  /* 存活 线程数 */
                          pthread_mutex_unlock(&(pool->lock));           //解锁

                         pthread_mutex_lock(&(pool->thread_counter));         
                         int busy_thr_num = pool->busy_thr_num;                  /* 获取忙着的线程数 */
                         pthread_mutex_unlock(&(pool->thread_counter));

                          /* 创建新线程 算法： 任务数大于最小线程池个数, 且存活的线程数少于最大线程个数时 如：30>=10 && 40<100*/
                              if (queue_size >= MIN_WAIT_TASK_NUM && live_thr_num < pool->max_thr_num)   //任务数大于线程池中最小的线程个数
		{
                                      pthread_mutex_lock(&(pool->lock));  
                                      int add = 0;

                                          /*一次增加 DEFAULT_THREAD 个线程*/  //是个固定值
                                              for (i = 0; i < pool->max_thr_num && add < DEFAULT_THREAD_VARY
                                             && pool->live_thr_num < pool->max_thr_num; i++)      //活着的线程数效于最大值
			{
                                                       if (pool->threads[i] == 0 || !is_thread_alive(pool->threads[i]))   // 线程是否活着。死了就在原位置创建新的
				{
                                                                     pthread_create(&(pool->threads[i]), NULL, threadpool_thread, (void *)pool);  //创建线程
                                                                       add++;                         //活着的数量++
                                                                      pool->live_thr_num++;
                                                                 }
                                                 }

                                                 pthread_mutex_unlock(&(pool->lock));
                                  }

                                /* 销毁多余的空闲线程 算法：忙线程X2  小于  存活的线程数 且 存活的线程数 大于 最小线程数时*/  //忙碌的线程占总线程的50%都没有
                               if ((busy_thr_num * 2) < live_thr_num  &&  live_thr_num > pool->min_thr_num)  //活着的线程数 大于最小线程
		{
                                         /* 一次销毁DEFAULT_THREAD个线程, 隨機10個即可 */
                                         pthread_mutex_lock(&(pool->lock));
                                         pool->wait_exit_thr_num = DEFAULT_THREAD_VARY;      /* 要销毁的线程数 设置为10 */
                                         pthread_mutex_unlock(&(pool->lock));

                                                for (i = 0; i < DEFAULT_THREAD_VARY; i++) 
			{
                                                  /* 通知处在空闲状态的线程, 他们会自行终止*/
                                                   pthread_cond_signal(&(pool->queue_not_empty));   //空闲的线程会阻塞在取任务处，并且管理线程设置了需要退出的线程数>0，满足子线程中的条件
                                                 }
                                }
                         }
 
    return NULL;
}









int threadpool_destroy(threadpool_t *pool)
{
    int i;
                 if (pool == NULL) 
	{
                       return -1;
                 }
               pool->shutdown = true;

               /*先销毁管理线程*/
              //pthread_join(pool->adjust_tid, NULL);

                  for (i = 0; i < pool->live_thr_num; i++) 
	{
                         /*通知所有的空闲线程*/
                          pthread_cond_broadcast(&(pool->queue_not_empty));
                }


    /*for (i = 0; i < pool->live_thr_num; i++) 
     {
           pthread_join(pool->threads[i], NULL);
    }*/


    threadpool_free(pool);

    return 0;
}





int threadpool_free(threadpool_t *pool)
{
                if (pool == NULL) 
	{
                     return -1;
                }

                   if (pool->task_queue)   //free线程ID
	{
                      free(pool->task_queue);
                 }

                 if (pool->threads) 
	{
        free(pool->threads);                                              //把 线程 锁和条件变量 free
        pthread_mutex_lock(&(pool->lock));
        pthread_mutex_destroy(&(pool->lock));
        pthread_mutex_lock(&(pool->thread_counter));
        pthread_mutex_destroy(&(pool->thread_counter));
        pthread_cond_destroy(&(pool->queue_not_empty));
        pthread_cond_destroy(&(pool->queue_not_full));
                  }

    free(pool);
    pool = NULL;

    return 0;
}










int threadpool_all_threadnum(threadpool_t *pool)
{
    int all_threadnum = -1;

    pthread_mutex_lock(&(pool->lock));
    all_threadnum = pool->live_thr_num;
    pthread_mutex_unlock(&(pool->lock));

    return all_threadnum;
}











int threadpool_busy_threadnum(threadpool_t *pool)
{
    int busy_threadnum = -1;

    pthread_mutex_lock(&(pool->thread_counter));
    busy_threadnum = pool->busy_thr_num;
    pthread_mutex_unlock(&(pool->thread_counter));

    return busy_threadnum;
}










int is_thread_alive(pthread_t tid)
{
    int kill_rc = pthread_kill(tid, 0);     //发0号信号，测试线程是否存活
               if (kill_rc == ESRCH) 
	{
                        return false;
                 }

    return true;
}









/*测试*/ 

#if 1
/* 线程池中的线程，模拟处理业务 */
void *process(void *arg)
{
    printf("thread 0x%x working on task %d\n ",(unsigned int)pthread_self(),*(int *)arg);
    sleep(1);
    printf("task %d is end\n", *(int *)arg);

    return NULL;
}














int main(void)
{
    /*threadpool_t *threadpool_create(int min_thr_num, int max_thr_num, int queue_max_size);*/
    threadpool_t *thp = threadpool_create(3,100,100);   /*创建线程池，池里最小3个线程，最大100，队列最大100*/
    printf("pool inited");

    //int *num = (int *)malloc(sizeof(int)*20);
    int num[20], i;
                  for (i = 0; i < 20; i++)             //连续添加20个任务。
	 {
                      num[i]=i;
                       printf("add task %d\n",i);
                       threadpool_add(thp, process, (void*)&num[i]);   /* 向线程池中添加任务 */
                  }

    sleep(10);                                          /* 等子线程完成任务 */        也可以join 循环判断
    threadpool_destroy(thp);

    return 0;
}

#endif
